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Biomedical subjects

H Imhof

Publications and source records attributed to H Imhof.

At least 217 records · Page 12Linked to original sources
PubMed1990

[CT and MRT in mediastinal and hilar space-occupying lesions].

Thirty-eight patients with mediastinal and/or hilar masses were imaged by computed tomography (CT) and magnetic resonance imaging (MRI). Results were analyzed retrospectively regarding the ability to demonstrate the masses, their number, size, definition, location and tissue characteristics. CT and MRI showed equivalent results in 32 cases; additional information was obtained in two patients by CT, in four patients by MRI. In view of the specific advantages and limitations of both CT and MRI we believed that in patients with mediastinal and/or hilar masses, contrast enhanced CT remains the procedure of choice after performing plain chest radiographs; in certain cases MRI will prove useful for further evaluation.

Adolescent↗
PubMed1989

[Gd-DTPA in the MR diagnosis of pituitary adenomas].

25 patients with surgically (n = 14) and/or biochemically (n = 20) confirmed pituitary adenomas were examined on a 1.5 T superconducting MR system by means of multislice spin-echo technique, 3 mm thick sections and a 256 x 256 matrix. T1-weighted sagittal and coronal sections were obtained before and after administration of Gd-DTPA (0.1 mmol./kg. BW). 13 microadenomas and 12 macroadenomas were found. In unenhanced T1-weighted images 48% of the adenomas were isointense, 48% were hypointense and 4% were hyperintense. 58% of the adenomas enhanced to a lesser degree, 15% enhanced to a higher degree than the normal pituitary gland. 12% showed equal enhancement and 15% showed hypointense and hyperintense areas simultaneously. In 3 patients (12%) there was evidence of adenoma only in the enhanced images. The delineation of the adenoma from the cavernous sinus was possible in 95% of the enhanced, but only in 25% of the native scans.

Adenoma↗
PubMed1989

[Fibrous dysplasia: its appearance in the magnetic resonance tomogram].

Eleven patients with proven fibrous dysplasia of the skeleton (FD) were examined using magnetic resonance imaging (MRI). Almost constantly T1-weighted hypointense, T2-weighted hyperintense (cystic) as well as T1- and T2-weighted hypointense (fibrous) areas within the lesion could be demonstrated, the latter of which always exhibited either moderate or marked enhancement following intravenous application of Gd-DTPA, resulting in a typical appearance. Furthermore, T1- and T2-weighted hyperintense areas within the lesion were seen in many patients due to focal hemorrhage. No linear time correlation between the clinical symptom pain and focal areas of hemorrhage as shown by MRI, could be established.

Adult↗
PubMed1989

Gd-DTPA enhanced high resolution MR imaging of pituitary adenomas.

Thirty-eight patients with surgically or biochemically confirmed pituitary adenomas were examined on a 1.5 T MRI system by means of spin echo technique with 3 mm slice thickness. T1 weighted sagittal and coronal sections were obtained before and after the administration of Gd-DTPA. Compared with the normal pituitary anterior lobe, 8% of the adenomas were hyperintense, 45% were isointense, 42% were hypointense and 5% were inhomogeneously intense. After Gd-DTPA administration, 13% enhanced to a greater degree, 10% to the same, and 57% to a lesser degree than the normal pituitary tissue. Twenty percent showed inhomogeneous enhancement. In 10%, there was evidence of adenoma only in the enhanced images. The delineation of the adenoma from the cavernous sinus was improved from 47% in unenhanced scans to 91% after Gd-DTPA administration.

Adenoma↗
PubMed1989

Invasive pulmonary aspergillosis: evaluation with MR imaging.

Eleven patients with suspected invasive pulmonary aspergillosis underwent magnetic resonance (MR) imaging. Images were obtained with standard spin-echo sequences and electrocardiographic triggering before and after intravenous administration of gadolinium diethylenetriaminepentaacetic acid. Thirty-seven of 48 lesions seen on MR images were nodular infiltrates; 34 of these had a targetlike appearance, with hypointense centers and iso- or hyperintense rims. Twenty-three of 37 nodular lesions contained areas of hyperintensity on T1-weighted images. All 37 had enhanced rims on postcontrast MR images. The remaining 11 lesions were segmental infiltrates, seven of which were predominantly hyperintense on T1-weighted images. In one patient with nodular lesions, MR imaging findings were correlated with those from pathologic analysis of a resected upper lobe. Areas of hyperintensity corresponded to subacute hemorrhage permeated by Aspergillus organisms. The authors believe that the typical targetlike appearance of nodular lesions on MR images and the potential that MR imaging has to reveal hemorrhagic content will prove useful in the early diagnosis of invasive pulmonary aspergillosis.

Aspergillosis↗
PubMed1989

[Gadolinium-DTPA in magnetic resonance tomography. Clinical use--indications].

Magnetic resonance tomography was performed on 158 patients with different indications before and after the administration of contrast medium. The MR examination included various plain T1 and T2 weighted spin echo sequences as well as T1 weighted examinations after intravenous application of Gadolinium-DTPA ("Magnevist", Schering AG) in a dosage of 0.1 mmol/kg body weight. The following conclusions were drawn: The sensitivity of MR in detecting brain tumors, acoustic neuromas and pituitary adenomas was improved considerably after the administration of "Magnevist". To diagnose the type of tumor, the criteria which apply to Gd-DTPA are similar to those used for iodine-containing contrast medium in CT. In about 2/3rds of the cases, delineation of pathological tissues from surrounding edema and normal structures was better than in plain films. Hence, accurate, pretherapeutic staging of bronchial carcinomas and an exact definition of the expansion of the malignancies in the muscle-skeleton system were possible. In respect of tumors in the region of the base of the skull, we could omit T2-weighted sequences without noticeable loss of diagnostically relevant information; the examination time could thus be shortened by about 12 minutes.

Adolescent↗
PubMed1989

[Fibrosing mediastinitis].

Fibrosing mediastinitis is a rare entity either idiopathic or caused by granulomatous disease. Plain film findings mainly show widening of the upper half of the anterior mediastinum, whereas CT delineates more clearly the exact location of the mediastinal mass and the extent of compromise of mediastinal structures. Although vessels surrounded by the fibrous mass are typically smoothly bordered and only rarely displaced, diagnosis can only be suspected together with the patients history and clinical course.

Adult↗
PubMed1988

[Magnetic resonance tomography as a localization method in hyperparathyroidism].

Magnetic Resonance Imaging (MRT) was performed in 36 consecutive patients with hyperparathyroidism. MR tomograms of 31 patients were evaluated and compared with the results of operation and histology (n = 29). In the remaining 5 patients MR examination was not completed, due to claustrophobia or motion artefacts. MR examinations were performed in 2 superconductive magnets (0.5 and 1.5 Tesla). A surface coil with following spinecho sequences was used: SE: TR/TE: 550-700/15-30; 2000/22-100. All patients were subjected to additional sonography. Out of 28 parathyroid adenomas 25 were identified on MR tomograms (sensitivity: 73%, specificity: 90%). However, only 2 out of 6 hyperplastic parathyroid glands were localized on MR tomograms. Lesions missed on MR tomograms measured 15 mm and less in diameter. It is characteristic that parathyroid adenomas showed isointense MR signal to the thyroid (SE 550/30 and hyperintense MR signal to fat (SE 2000/100). Different signal intensities of the adenomas were observed in 25% of the cases. MR imaging is a valuable diagnostic method for preoperative localisation of parathyroid adenomas. We think that MR imaging should be performed when sonography and subtraction scintigraphy are not able to identify a suspected adenoma in the same location.

Adenoma↗
PubMed1988

[CT staging of laryngeal carcinoma].

In the pre-operative staging of laryngeal carcinoma CT is of great clinical importance. We examined 20 cases of laryngeal cancer. In 20% of the cases, the CT evaluation indicated more advanced stages, thereby correcting the results of clinical staging. In 65% of the cases, clinical staging showed the same results as CT. 3 glottis tumours (15% of the patients) could not be identified by CT.

Adult↗
PubMed1987

[Value of CT following surgery for rectal cancer (a prospective study)].

The results of computed tomography of 48 patients after operation on rectal carcinoma who underwent close-meshed computer tomographic examinations are given in a prospective study. (First examination 6 weeks after operation, further examinations at intervals of 3 months, mean observation time: 12 months). The results of follow-up by means of computer tomographic examination are compared with clinical examinations and control of CEA levels. The use of computer tomographic examination resulted in 43 confirmed negative, 3 confirmed positive and 2 false negative findings (including cases with CT-aided fine needle biopsy). These results give an accuracy of 96% and thus exceed clinical examination and controls of CEA-level. How far early diagnosis of local recurrence of rectal cancer influences survival time, can be answered after completion of this study in the next few years.

Adenocarcinoma↗
PubMed1986

[Addison's disease with enlarged adrenal glands in sonography and computer tomography. Differential diagnostic considerations based on 2 cases of tuberculous adrenalitis].

One of the major causes of chronic adrenal insufficiency (Addison's disease) is tuberculous adrenalopathy. Since sonography and computed tomography have become generally available in recent years and are of potential help in the diagnosis of this disease the merits of these methods are discussed in the light of 2 cases of adrenal tuberculosis, followed by a review of the literature. Adrenal calcification is the most significant, although not specific sign of adrenal insufficiency due to tuberculosis. Computed tomography has proven to be the method of choice in the non-invasive diagnosis of tuberculous adrenalopathy and in the monitoring of tuberculostatic treatment in this disease. Sonography is helpful as a preliminary investigation.

Addison Disease↗
PubMed1986

[Significance of computerized tomography in middle ear diagnosis].

Due to the important improvement represented by the latest computed tomography (CT) technology in respect of detail and excellent contrast resolution normal and pathological structures of the inner and middle ear can be visualised. The clinical and diagnostic value of CT in comparison to standard x-rays and tomography is prospectively evaluated on the basis 74 patient examinations. Today CT is unsurpassed in the diagnosis of cholesteatomas and glomus tumours and ranks first among all imaging modalities. Chronic inflammatory diseases and deformities of the middle ear can be evaluated in most cases on the basis of standard x-rays and tomography. The importance of CT is primarily complementary, except in preoperative cases. Fractures should be visualised first via standard x-rays. In cases of questionable complications (e.g. tympanic or intracranial haematomas), CT should be the next step. Conventional tomograms are not necessary.

Adolescent↗
PubMed1986

[Computerized tomography (CT) and nuclear magnetic resonance tomography (MRT) in the diagnosis of liver metastasis].

Sonography and computer-tomography (CT) are the "gold-standard" in the imaging of liver-metastasis larger than 1 to 2 cm in diameter (overall-accuracy: greater than 90%). The magnetic resonance tomography (MRT) also allows the imaging of liver-metastasis due to the different relaxation-times of normal liver-tissue and metastasis. In agreement with other authors MRT shows an almost equal accuracy in the diagnosis of liver-metastasis as CT (16 patients, average age 58 years). The significantly reduced detail-resolution of MRT in comparison with CT is overcome by the gain in contrast-resolution. The smaller imaging extent in MRT is disadvantageous in the evidence of pleural effusions, bone-metastasis or lymph-node enlargements. A pathognomic differential-diagnosis of liver-metastasis by MRT is impossible. In the near future MRT of liver-metastasis can be improved by "flash"-images and may replace CT. On the other hand screening for liver-metastasis with sonography is unchallenged by MRT.

Adolescent↗